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        "http://www.w3.org/TR/html4/loose.dtd">
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    <title>设置DIV块</title>
    <meta charset="UTF-8">
    <style>
        .st{
            background-color:black;
            color:white;
            margin:20px;
            padding:20px;
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        span.setcolor {color:red;}
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<div class = "st">
    <h2>
        London
    </h2>
    <p>
        London is the capital city of England.
        It is the most populous city in the United Kingdom,
        with a metropolitan area of over 13 million inhabitants.
    </p>
</div>

<p><span class="setcolor">span</span>元素是行内元素，<span class="setcolor">能够用作文本的容器。</span></p>
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